The present invention is directed to a refrigerant transfer system. More specifically, the present invention is directed to a highly versatile yet portable system which can evacuate one refrigeration system or refrigerant vessel, re-pressurize the vapor component of the refrigerant, and transfer the refrigerant to another refrigerant system or vessel, particularly when a low pressure refrigeration system is involved.
Previous recycle/recovery systems have been meant for use with high pressure refrigeration systems such as those used in automobile air conditioning units. The previous systems are designed so that an untrained service person can service an automobile air conditioning unit by simply making a few hose connections and initiating an automatic process. Such a system is shown in U.S. Pat. No. 4,805,416 to Manz et al. This system is intended for operation by relatively unskilled personnel with minimum operator intervention. However, in each embodiments shown in FIGS. 1-8 of Manz et al., the required sequence of an inlet 32, a strainer 30, a pressure switch 42, a valve 28, 78, a heat exchange/oil separation unit 26, a compressor 22, the heat exchange/oil separation unit 26, a pressure switch 70 and a container 58 limit the versatility of this unit while contributing greatly to its expense.
A much better portable recovery system is disclosed in the system disclosed in Degier et al. as identified above, which is not admitted to be prior art. Degier et al. disclose a pump and a condenser connected in various configurations with the refrigerant head and sump of a chiller and a holding tank to transfer a refrigerant from one to the other. The system optionally includes filtering, dehydrating, and other auxiliary equipment as well as equipment for transferring the refrigerant. The components used to carry out these operations are desirably mounted on a cart or other fixed or portable platform so they can be transported and used together.
The present invention is a further improvement of the apparatus and methods disclosed by Degier et al.
Such apparatus would desirably have different pumps at different stages of the recovery of refrigerant from a chiller or other vessel. A high volume pump would be desirable for recovery of refrigerant who's vapor density is already high, thus requiring relatively less compression and thus minimizing the time required for a complete recovery. On the other hand, a high pressure pump would be desirable to draw a vacuum in the tank from which the refrigerant is transferred after its liquid contents have been exhausted and only refrigerant vapor remains. Conventional refrigerant recovery units are only equipped with a single pump which is a compromise between these different needs.
A refrigerant recovery unit or similar apparatus should provide a high recovery level of the refrigerant, consistent with ever-tightening government regulations and industry standards mandating stringent measures to prevent the release of noxious or environmentally undesirable refrigerant vapor into the atmosphere or into a work environment when a refrigeration unit is repaired, recharged, or decommissioned.
Refrigerant recovery apparatus is needed in which one component, such as a particular pump or the motor to drive it, can be adapted to different configurations instead of providing specialized components for each configuration. For example, a refrigerant recovery unit or similar apparatus would desirably use one motor to drive both a high-volume pump and a high-pressure pump.
A refrigerant recovery unit is desirably both versatile and easily used by a trained operator.